The present invention relates to a chassis support having a hollow support section consisting of a self-hardening aluminum alloy as well to a process for manufacturing the support.
EP 0 548 859 B1 discloses a process for the manufacture of chassis supports in which the chassis supports are produced from straight-bead welded tubes made of a self-hardening aluminum alloy. Such a tube is produced from a sheet metal plate made of an AlMgMn-alloy. The sheet metal plate is correspondingly longitudinally curved and welded along the forming straight bead. These straight-bead welded tubes are then cold-formed by internal high-pressure metal forming and are previously intermediately annealed. With this forming technique, the adaptation of the cross-sections of the chassis support to the respective local stresses is,. however, possible only to a limited extent.
It is an object of the present invention to provide a chassis support which has a weight which is as low as possible while the operating stability is simultaneously very high over its entire length.
This object has been achieved in accordance with the present invention that the hollow support section comprises a box-type manner of a top shell and a bottom shell which are each made of an aluminum sheet consisting of the self-hardening aluminum alloy. The top shell and the bottom shell are each welded together on the longitudinal side in the region of their mutually adjoining section legs. As a result of this construction, large abrupt changes of cross-section as well as sudden transitions for the chassis support can be provided. Local reinforcements or nodes can be mounted on the interior side of these box sections. This arrangement considerably reduces the weight of the chassis support, particularly because corresponding section moduli of the chassis support can be coordinated in a targeted manner with the respective local stress. One advantage of the present invention is that the chassis support has a very low weight while its stability is simultaneously excellent.
According to a further feature of the present invention, the longitudinally extending weld seams are displaced in low-stress regions of the box-shaped hollow support section. As a result, the stability drop in the weld seam region does not have any significant effect on the operating stability of the chassis support.
Yet a further advantageous feature of the present invention resides in the provision of reinforcing devices for highly stressed regions of the hollow support section assigned to the top and bottom shells. These reinforcing devices are used in a targeted manner on the respective highly stressed regions of the chassis support.
Furthermore, several reinforcing sheets can be provided as reinforcing devices distributed along the length of the hollow support section. The reinforcing sheets can be, in the case of overlapping top and bottom shells, arranged inside the larger shell and have positioning noses on which the section legs of the other shell rest and the section legs of the outer shell simultaneously overlap those of the inner shell. As a result, one shell can be positioned with respect to the other shell for a subsequent welded connection.